Discovery of TP0597850: A Selective, Chemically Stable, and Slow Tight-Binding Matrix Metalloproteinase-2 Inhibitor with a Phenylbenzamide-Pentapeptide Hybrid Scaffold.

Matrix metalloproteinase-2 (MMP2) is a zinc-dependent endopeptidase and a promising target for various diseases, including cancer and fibrosis. Herein, we report the discovery of a novel MMP2-selective inhibitor with high chemical stability and slow tight-binding features. Based on the degradation mechanism of our small-molecule-peptide hybrid 1, the tripeptide linker {5-aminopentanoic acid [Ape(5)]-Glu-Asp} of 1 was replaced by a shorter linker (γ-D-Glu). Phenylbenzamide was suitable for the new generation of MMP2 inhibitors as an S1' pocket-binding group. The introduction of (4S)-aminoproline dramatically increased the chemical stability while maintaining high subtype selectivity because of its interaction with Glu130. TP0597850 (18) exhibited high stability over a wide range of pH values as well as potent MMP2 inhibition (Ki = 0.034 nM) and ≥2000-fold selectivity determined using the inhibition constants. A kinetic analysis revealed that it possesses slow tight-binding nature with a long MMP2 dissociative half-life (t1/2 = 265 min).

Discovery of Aryloxyphenyl-Heptapeptide Hybrids as Potent and Selective Matrix Metalloproteinase-2 Inhibitors for the Treatment of Idiopathic Pulmonary Fibrosis.

Matrix metalloproteinase-2 (MMP2) is a zinc-dependent endopeptidase that plays important roles in the degradation of extracellular matrix proteins. MMP2 is considered to be an attractive target for the treatment of various diseases such as cancer, arthritis, and fibrosis. In this study, we have developed a novel class of MMP2-selective inhibitors by hybridizing the peptide that binds to a zinc ion and S2-S5 pockets with small molecules that bind to the S1' pocket. Structural modifications based on X-ray crystallography revealed that the introduction of 2,4-diaminobutanoic acid (Dab) at position 4 dramatically enhanced MMP2 selectivity by forming an electrostatic interaction with Glu130. After improving the metabolic and chemical stability, TP0556351 (9) was identified. It exhibited potent MMP2 inhibitory activity (IC50 = 0.20 nM) and extremely high selectivity. It suppressed the accumulation of collagen in a bleomycin-induced idiopathic pulmonary fibrosis model in mice, demonstrating the efficacy of MMP2-selective inhibitors for fibrosis.

Antipsychotic profiles of TASP0443294, a novel and orally active positive allosteric modulator of metabotropic glutamate 2 receptor.

Glutamatergic dysfunction has been implicated in psychiatric disorders such as schizophrenia. The stimulation of metabotropic glutamate (mGlu) 2 receptor has been shown to be effective in a number of animal models of schizophrenia. In this study, we investigated the antipsychotic profiles of (2S)-5-methyl-2-{[4-(1,1,1-trifluoro-2-methylpropan-2-yl)phenoxy]methyl}-2,3-dihydroimidazo[2,1-b][1,3]oxazole-6-carboxamide (TASP0443294), a newly synthesized positive allosteric modulator of the mGlu2 receptor. TASP0443294 potentiated the response of human mGlu2 and rat mGlu2 receptors to glutamate with EC50 values of 277 and 149 nM, respectively, without affecting the glutamate response of human mGlu3 receptor. TASP0443294 was distributed in the brain and cerebrospinal fluid after peroral administration in rats. The peroral administration of TASP0443294 inhibited methamphetamine-induced hyperlocomotion in rats, which was attenuated by an mGlu2/3 receptor antagonist, and improved social memory impairment induced by 5R,10S-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine hydrogen maleate (MK-801) in rats. Furthermore, TASP0443294 reduced the ketamine-induced basal gamma hyperactivity in the prefrontal cortex and suppressed rapid eye movement (REM) sleep in rats. These findings indicate that TASP0443294 is an mGlu2 receptor positive allosteric modulator with antipsychotic activity, and that the suppression of aberrant gamma oscillations and REM sleep could be considered as neurophysiological biomarkers for TASP0443294.

Neurophysiologic and antipsychotic profiles of TASP0433864, a novel positive allosteric modulator of metabotropic glutamate 2 receptor.

Excess glutamatergic neurotransmission has been implicated in the pathophysiology of schizophrenia, and the activation of metabotropic glutamate 2 (mGlu2) receptor may exert antipsychotic effects by normalizing glutamate transmission. In the present study, we investigated the neurophysiologic and antipsychotic profiles of TASP0433864 [(2S)-2-[(4-tert-butylphenoxy)methyl]-5-methyl-2,3-dihydroimidazo[2,1-b][1,3]oxazole-6-carboxamide], a newly synthesized positive allosteric modulator (PAM) of mGlu2 receptor. TASP0433864 exhibited PAM activity at human and rat mGlu2 receptors with EC50 values of 199 and 206 nM, respectively, without exerting agonist activity at rat mGlu2 receptor. TASP0433864 produced a leftward and upward shift in the concentration-response curve of glutamate-increased guanosine 5'-O-(3-[(35)S]thio)triphosphate binding to mGlu2 receptor. In contrast, TASP0433864 had negligible activities for other mGlu receptors, including mGlu3 receptor, and did not have any affinity for other receptors or transporters. In hippocampal slices, TASP0433864 potentiated an inhibitory effect of DCG-IV [(2S,2'R,3'R)-2-(2',3'-dicarboxylcyclopropyl)glycine], a mGlu2/3 receptor agonist, on the field excitatory postsynaptic potentials in the dentate gyrus, indicating that TASP0433864 potentiates the mGlu2 receptor-mediated presynaptic inhibition of glutamate release. Moreover, TASP0433864 inhibited both MK-801 [(5S,10R)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine hydrogen maleate]- and ketamine-increased cortical γ band oscillation in the rat cortical electroencephalogram, which have been considered to reflect the excess activation of cortical pyramidal neurons. The inhibitory effect of TASP0433864 on cortical activation was also observed in the mouse 2-deoxy-glucose uptake study. In a behavioral study, TASP0433864 significantly inhibited both ketamine- and methamphetamine-increased locomotor activities in mice and rats, respectively. Collectively, these findings indicate that TASP0433864 is a selective mGlu2 receptor PAM with antipsychotic activity, and the attenuation of excess glutamatergic neurotransmission may be involved in the action of TASP0433864.